1. Technical Field
The invention relates to a method for selecting a scanning frequency. Particularly, the invention relates to a method for selecting a scanning frequency for a touch panel and an electronic device using the same.
2. Related Art
As technology advances, touch panels gradually replace conventional keyboard input devices. Namely, more and more information products can receive operation commands through the touch panels. Generally, in order to provide power required for operating the information product or make the information product to support more levels of application, the information product is generally connected to other external devices, for example, a mobile phone can be connected to a charger for charging. Therefore, when the information product having a touch panel (which is simply referred to as the information product) is connected to the external device, a scanning frequency used to scan the touch panel of the information product is probably interfered by a working frequency of the connected external device. Now, due to the interference of the working frequency of the external device, a plenty of noises are generated in sensing results of the touch panel, which influences the performance of the touch panel.
According to the conventional technique, a high voltage or frequency hopping operation method is used to enhance the performance of the touch panel. The conventional frequency hopping operation is blindly and gradually decrease (or increase) the scanning frequency for the touch panel from a predetermined working frequency in a method non-related to the connected external device (peripheral component) until the performance of the touch panel reaches an acceptable range.
However, the above conventional frequency hopping operation method needs to spend a lot of time in blindly trying to find a better scanning frequency.